MRI, as a medical imaging technique, makes use of the property of nuclear magnetic resonance (NMR) to image nuclei of atoms inside the body. In a MRI system, a powerful magnetic field is generated to align the magnetization of some atomic nuclei in the body, and radio frequency fields may be introduced to systematically alter the alignment of this magnetization. This causes the nuclei to produce a rotating magnetic field detectable by a scanner—and this information on the rotating magnetic field is recorded to construct an image of the scanned area of the body.
As shown in FIG. 1, in the MRI system, a main magnet which generates the powerful magnetic field is disposed in a scanner room (i.e., magnet room) 11. Most of—the electronic devices 14 used in the MRI system, including a RF amplifier for generating the radio frequency fields, should be placed in a separate room (i.e., technical room) 12 so as to protect these electronic devices from a strong magnetic environment. The magnet room 11 should be shielded by an RF cage 13 to further prevent these electronic devices 14 being affected by the powerful magnetic field. The RF signal generated by the RF amplifier in the technical room 12, usually, is transmitted to the main magnet through a hole 15 in the wall of the magnet room 11 via a long cable—which may cause huge loss, resulting in the cost of MRI being high.
There is therefore a need in the art for techniques to efficiently provide the RF signal in a MRI system.